Flat, hands-free, convertible keplerian binoculars

ABSTRACT

Binoculars which are flat in the direction of view include two powerful Keplerian telescopes placed in two flat containers covering each eye and held by an eyeglass frame resting on the nose and ears; the binoculars can be easily converted into magnifying reading eyeglasses by touching a knob on the temple side of each telescope.

REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of my provisional patentapplication ‘Flat, Hands-Free, Convertible Keplerian Binoculars’ filedby PTO on Mar. 6, 1997 with application Ser. No. 60/038,045.

The structure of proposed binoculars, the optical diagram, opticalcomponents and their position and orientation are unchanged.

BACKGROUND OF THE INVENTION

The purpose of this invention is to replace existing magnifyingeyeglasses by more convenient and cosmetically attractive devices. Themagnifying eyeglass improve vision for the many millions of low visionpersons, including those suffering from macular degeneration.

Existing binoculars intended as low vision aids are not perfect. TheGalilean type binoculars have a narrow (about 5 degrees) field of viewand aberrations at the edge of the field. Existing Keplerian low visionbinoculars have good optical performance but they are bulky and heavy,projecting as much as three to four inches from the eye. Some devicesprovide the conversion of far distance binoculars into magnifyingreading glasses by putting so called reading caps on the objectivelenses which enables reading but with rather small depth of sharpness.

This invention overcomes the aforementioned problems with a new type ofKeplerian binoculars, each half of which is 18 mm thick (in thedirection of view) and just covers the eye of the user. The wholebinoculars' appearance is similar to the appearance of sunglasses. Thedesign is lightweight, comfortable to wear on the nose and ears. Thebinoculars have a front aperture of 24 mm and enable both near and farvision with high resolution.

A Special feature of the device is its convertibility. Just touching theknob no each temple side converts the far distance binoculars intomagnifying reading eyeglasses. For instance, a user, during a lecture,will be able to see the blackboard and after, a quick click, be able toread his/her notebook.

SUMMARY OF THE INVENTION

The invented binoculars have two telescopes hidden in two flatcontainers 18 mm thick and 60 mm in diameter, covering each eye. Thecontainers are attached to a spectacle frame. This makes the appearanceof binoculars similar to that of sunglasses, as shown in FIG. 1. Thebinoculars are light, and the weight is distributed close to theforehead, enabling a standard eyeglass frame to be used.

Placing telescopes in small flat containers is possible because of thespecial optical diagram of the telescopes. The axis of the objectivelens (2) and the axis of the eyepiece field lens (7) are vertical,perpendicular to the vision axis, as shown in FIG. 2. The needed longoptical path from the objective lens to the eyepiece is formed by fourflat mirrors positioned at 22.5 degree angle to the beam.

Conversion from far distance binoculars to magnifying reading eyeglasseswithout changing the magnification is accomplished by using anadditional plus lens (10) inserted approximately in the middle of theoptical path. This method provides at least twice larger depth ofsharpness than reading cups put on the objective lens. The additionalconverting lens (10) is driven by a spring mechanism with a knob on thetemple side of the telescope.

Despite the small dimensions, the binoculars are really powerful. Thefront aperture is 24 mm, magnification is 6x, the field of vision is 9degrees, the angular resolution is 20 angular seconds. The opticalsystem is completely corrected chromatically: the objective less and theeyepiece field lens are achromatic.

Focusing for the far vision range, from 2 yards to infinity, and alsofor the reading distance range is performed by rotating the focusingwheel on the temple side of each telescope.

The binoculars can be redesigned for varying degrees of magnificationwith corresponding changes in the field of vision.

BRIEF DESCRIPTION OF THE DRAWINGS

The Summary of the Invention and Detailed Description of PreferredEmbodiments are illustrated in the actual size drawings.

FIG. 1 is a front view of the binoculars,

FIG. 2 is a front view of one telescope with removed front cover.

FIG. 2A is a sectional view taken along line 2A—2A of FIG. 2.

FIG. 2B is a sectional view taken along line 2B—2B of FIG. 2.

FIG. 3 shows the eccentric mechanism that moves a plate with fourmirrors.

FIG. 3A shows the plate with four mirrors.

FIG. 4 shows the structure of the spring mechanism that moves theconverting lens. (The entrance mirror (1) and the rack-and-pinion (18)are removed).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate the invented flat binoculars. They consist oftwo Keplerian telescopes mounted on the spectacle frame (11). Eachtelescope has a light, rigid framework (12), so small that it covers thewearer's eye in the manner of ordinary eyeglasses. In the thickness ofeach telescope, an achromatic objective lens and a special type ofKoellner eyepiece are placed. The beam path begins at the entranceplanar mirror (1) inclined at 45 degrees to the front plane of thetelescope. From the entrance mirror the light beam travels through theobjective lens (2) which has a vertical axis. The purpose of this designis to reduce the thickness of the whole device: the thickness of theobjective lens is not added. The objective lens is achromatic and has anaperture of 24×16 mm.

The eyepiece is specially designed to attain the compensation for theresidual chromatic aberration of the objective lens as well as toprovide the required magnification, size and position of the exit pupil.This eyepiece of special Koellner type is properly short, it consists ofthe achromatic field lens (7) with 30 mm focal length, the plano-convexeye lens (9), and the plane mirror (8) inclined at 45 degrees to theaxis of the lens (7) and to the axis of the eye lens (9). The placementof the achromatic lens as the field lens is uncommon in the Koellnereyepiece where the eye lens is usually achromatic. The used diagramenables the eyepiece to be made shorter.

The incidental light reflected by the entrance mirror (1) passes throughthe objective lens (2) and then travel around the perimeter of theframework to the eyepiece, directed by four plane mirrors (3), (4), (5)and (6). The mirrors (3), (4), (5) and (6) are parallel in the visionaxis of the eye and inclined at 22.5 degrees to the beam path, they formthe reflecting system that works as two pentaprisms. But a pair ofmirrors is preferred over a pentaprisms, because the mirrors make thewhole geometrical beam path shorter and can fit into the small size ofthe telescope. If the length of the geometrical path in the prism is Land the refractive index of the glass is N=1.5, the use of the prismcauses the significant increase of the length of the beam path from theobjective lens to the pupil by the amount:

L(N−1)/N=L/3

Focusing of the telescope can be accomplished by moving a plate with thefour mirrors (3), (4), (5), (6) along the objective axis. An alternativeway of focusing is moving the objective lens instead of the reflectingsystem. As shown in FIG. 3, the plate (13) with the four mirrors can bedriven by the eccentric (14) connected with the wheel (15) on the templeside of each telescope. FIG. 2 shows the rack-and-pinion focusingmechanism (18) moving the objective lens.

Besides the distance range for far vision, the telescope has the seconddistance range for reading and detailed work. The commutation of rangesis made by inserting the +10 diopter lens (10) between the two pairs ofmirrors in the reflecting system. The converting +10 diopter lens (10)is driven up and down by a spring mechanism with a knob on eachtelescope. The depth of sharpness in the reading position is more than30 mm. The versatility of the invented binoculars is important for alow-vision person who needs assistance for both close-up and far vision.

The rack-and-pinion mechanism shown in FIG. 2, the eccentric mechanismdepicted in FIG. 3, and the spring mechanism shown in FIG. 4 are notinvolved in the claims of the invention and can be improved.

The converting lens (10) in FIG. 4 is pulled by a thin belt stretched ontwo pulleys and is pushed back by the spring (16). The knob (17) on thetemple side of binoculars pulls the belt and is stopped by the stopperflat spring (21). The stopper is released by the pin inside the knob(17).

The front cover (19) of each telescope (in FIG. 1) is opaque except thetransparent sector (20) glued into the plastic cover (19). Thistransparent sector transmits light to the entrance mirror (1). Becausethe mirror is inclined at 45 degrees to the vision axis, this sectorlooks dark.

Each telescope is attached to the frame (11) with screws. It allows theselection of a frame size appropriate to a user's pupil distance.

Some features of the present invention are similar to those of thepocket telescope of U.S. Pat. No. 5,321,547, but there are significantdifferences in design and application. The invented binoculars containtwo telescopes; each of them just covers the eye and is twice smallerthan the existing pocket telescope because of the different opticaldiagram. Despite the small overall size each invented telescope has theaperture area 4 times larger than the mentioned pocket telescope. Otheradvantages of the present invention are: comfortable to wear (likeeyeglasses), hands-free, two operating modes.

What is claimed is:
 1. Binoculars which are generally flat in adirection of view, comprising two Keplerian telescopes in two flatcontainers attached to a spectacle frame, each said telescope is to belocated in front of an eye socket of a user, each said telescopeincludes an objective and an eyepiece and has a folded optical pathdirected by four planar mirrors between the objective and the eyepiece,each said telescope has an entrance planar mirror turned at 45 degreesto a vision axis of the user, each said telescope has a means forselectively inserting and removing a converting lens into and from theoptical path between the objective and the eyepiece in order to allow auser to convert said binoculars into reading magnifying eyeglasseswithout changing the magnification.
 2. Binoculars according to claim 1,wherein each said telescope has a thickness not larger than 18 mmmeasured along the vision axis from the front edge of said entranceplanar mirror to the last surface of the eye lens in the eyepiece, eachsaid telescope has the objective lens with a horizontal dimension notless than 24 mm, each said telescope has a magnification not less than6x, and the product of the magnification value multiplied by field ofview angle in degrees is not less than
 50. 3. Binoculars according toclaim 1, wherein the objective and the eyepiece, in each said telescope,are chromatically corrected.
 4. Binoculars according to claim 1, whereineach said telescope includes said entrance planar mirror turned at 45degrees to the vision axis and at 45 degrees to the objective lens axis.5. Binoculars according to claim 1, wherein all four said planar mirrorsdirecting the optical path between the objective and the eyepiece, ineach said telescope, are parallel to the vision axis and inclined at22.5 degrees to the beam path.
 6. Binoculars according to claim 1,wherein each said telescope includes said converting lens which is apositive lens stored in a provided space between the objective and theeyepiece, said converting lens has a focal length longer than thedistance between said converting lens and the objective lens and isinsertable into the optical path close to the middle point of saidoptical path by mechanical means in order to change the range of saidtelescope from far vision to reading distance vision.
 7. Binocularswhich are generally flat in a direction of view, comprising twoKeplerian telescopes in two flat containers attached to a spectacleframe, each said telescope is to be located in front of an eye socket ofa user, each said telescope includes an objective and an eyepiece andhas a folded optical path directed by four planar mirrors between theobjective and the eyepiece, each said telescope has an entrance planarmirror turned at 45 degrees to a vision axis of the user, and a lensmounted between the objective and the eyepiece for providing closevision.
 8. Binoculars according to claim 7, wherein each said telescopehas a thickness not larger than 18 mm measured along the vision axisfrom the front edge of said entrance planar mirror to the last surfaceof the eye lens in the eyepiece, each said telescope has the objectivelens with a horizontal dimension not less than 24 mm, each saidtelescope has a magnification not less than 6x, and the product of themagnification value multiplied by field of view angle in degrees is notless than
 50. 9. Binoculars according to claim 7, wherein the objectiveand the eyepiece, in each said telescope, are chromatically corrected.10. Binoculars according to claim 7, wherein each said telescopeincludes said entrance planar mirror turned at 45 degrees to the visionaxis and at 45 degrees to the objective lens axis.
 11. Binocularsaccording to claim 7, wherein all four said planar mirrors directing theoptical path between the objective and the eyepiece, in each saidtelescope, are parallel to the vision axis and inclined at 22.5 degreesto the beam path.
 12. Binoculars according to claim 7, wherein each saidtelescope includes said lens mounted between the objective and theeyepiece, and said lens is a positive lens which has a focal lengthlonger than the distance between said lens and the objective and ismounted close to the middle point of the optical path in order toprovide close vision.